/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.streaming.api.functions.sink;

import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.functions.util.PrintSinkOutputWriter;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.operators.StreamingRuntimeContext;

/**
 * Implementation of the SinkFunction writing every tuple to the standard
 * output or standard error stream.
 *
 * <p>
 * Four possible format options:
 *	{@code sinkIdentifier}:taskId> output  <- {@code sinkIdentifier} provided, parallelism > 1
 *	{@code sinkIdentifier}> output         <- {@code sinkIdentifier} provided, parallelism == 1
 *  taskId> output         				   <- no {@code sinkIdentifier} provided, parallelism > 1
 *  output                 				   <- no {@code sinkIdentifier} provided, parallelism == 1
 * </p>
 *
 * @param <IN> Input record type
 */
@PublicEvolving
public class PrintSinkFunction<IN> extends RichSinkFunction<IN> {

	private static final long serialVersionUID = 1L;

	private final PrintSinkOutputWriter<IN> writer;

	/**
	 * Instantiates a print sink function that prints to standard out.
	 */
	public PrintSinkFunction() {
		writer = new PrintSinkOutputWriter<>(false);
	}

	/**
	 * Instantiates a print sink function that prints to standard out.
	 *
	 * @param stdErr True, if the format should print to standard error instead of standard out.
	 */
	public PrintSinkFunction(final boolean stdErr) {
		writer = new PrintSinkOutputWriter<>(stdErr);
	}

	/**
	 * Instantiates a print sink function that prints to standard out and gives a sink identifier.
	 *
	 * @param stdErr True, if the format should print to standard error instead of standard out.
	 * @param sinkIdentifier Message that identify sink and is prefixed to the output of the value
	 */
	public PrintSinkFunction(final String sinkIdentifier, final boolean stdErr) {
		writer = new PrintSinkOutputWriter<>(sinkIdentifier, stdErr);
	}

	@Override
	public void open(Configuration parameters) throws Exception {
		super.open(parameters);
		StreamingRuntimeContext context = (StreamingRuntimeContext) getRuntimeContext();
		writer.open(context.getIndexOfThisSubtask(), context.getNumberOfParallelSubtasks());
	}

	@Override
	public void invoke(IN record) {
		writer.write(record);
	}

	@Override
	public String toString() {
		return writer.toString();
	}
}
